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Safety of unorthodox immunotherapy regimen

6/15/2014
I have a fellow physician as a patient with fairly significant asthma, now responding quite well to Omalizumab. Our plan was to start subcutaneous allergen immunotherapy once the patient has been on Omalizumab for 3-4 months. The patient's work schedule is 1 week on and 1 week off. During her work week, she is extremely busy and not able to come for allergen immunotherapy. During her week off (while still on lower concentration of allergen extracts), she can come in twice a week, with 2 days in between the injections. For example, during the off-work-week, she can come on a Tuesday and Friday for IT, then she is not able to come until the Tuesday (11 days from the previous Friday) for the injection. The plan it to keep her on Omalizumab till she reaches maintenance dose of IT and is on a monthly schedule.

I needed your advice of whether the above allergen IT schedule would be safe for her (as she is going to be on Omalizumab as well). When we get to higher concentrations of extract (1:10, 1:1), can we still continue the same aforementioned schedule (twice a week on the week on) during the build-up phase?

A:

Thank you for your inquiry.

Unfortunately, I cannot give you any evidence-based opinion as to the safety of the immunotherapy regimen you are proposing. This is because I know of no study that has investigated this regimen and compared its safety to more orthodox programs of treatment. However, my guess is that it would be as safe as standard therapy regimens, but in this situation, the only opinion is hypothetical.

However, if you are worried about the safety of immunotherapy, there are other options for you. You mentioned that you had planned to stop omalizumab when you reached the maintenance dose. This certainly is a feasible strategy, but I would mention to you that these two treatments are not interchangeable. Omalizumab and immunotherapy act through different mechanisms, and immunotherapy may not be an adequate substitute for omalizumab in your situation. For example, omalizumab has been shown to be effective not only in allergic but also in nonallergic asthma (1-3). Thus, you cannot be sure that immunotherapy will substitute for omalizumab in your patient, and the question then becomes, since she is under control, and since you are worried about the safety of an unorthodox immunotherapy regimen, an alternative would be to simply continue her on omalizumab without the addition of immunotherapy.

There is of course no "right" or "wrong" answer to this question, but it is something that you could consider as another strategy which would alleviate concern over the unorthodox regimen of immunotherapy.

Thank you again for your inquiry and we hope this response is helpful to you.